Guided: a banking CLI

From here through the ledger becomes an app we build one program. Same idea, more language each chapter, then modules, then a live API.

What it will do by the last lesson:

• Print a greeting (this page)
• Record deposits and withdrawals in cents
• Store them in a list and loop a balance
• Reject overdrafts with a visible error
• Split into modules
• Serve accounts and a ledger over Keel and pack a ship

Start a CLI:

buraaq new ledger --cli
cd ledger

Replace src/main.bq with:

fn main() {
    println("Ledger ready")
}

buraaq run

println imports itself. There is no use list yet. We use cents (int) so we do not fight floating-point money. 5000 means $50.00.

The path

1. Numbers and text
2. Arrays and lists
3. Loops
4. Functions
5. Structs
6. Errors
7. Modules: split the files
8. The ledger becomes an app: Keel + pack

Do not skip to Servers until this ledger compiles in your head. Then we put the same idea on the network without changing language.